We have been encouraged to eat more plants and less animals. Various writers have suggested it is healthier for our bodies and our planet. I have no objections to a mostly plant-based diet as long as attention is paid to protein requirements and micronutrition. However, since little things in animal products (some essential like B12, some that can be created in our bodies but perhaps not in the amounts we need, such as creatine) seem to be very important for the brain, it’s interesting to look at the literature on vegetarian diets and mental health. Here is the latest (and the best) observational study: Vegetarian diet and mental disorders: results from a representative community survey.

It's a German study, and for a large population-based retrospective observational design, it's actually fairly thorough and sensible. And if you are a vegetarian, it certainly doesn't say that vegetarianism causes mental health problems. But in all but two studies done in the past, vegetarianism has been linked with higher rates of depression, anxiety, and particularly eating disorders (bingeing, restricting, and purging behaviors). But to be perfectly honest, all those studies had some serious limitations (they were small, done special populations, and often measures based on just a few answers to general survey questions). I've reviewed a few of them. (My favorite has to be the one where they calculated arachidonic acid ingested to the hundredth of a gram based on data from a food frequency questionnaire, which seems very unlikely to be accurate) I don't think it is a coincidence that the two positive studies were done by the same group of researchers in the Seventh Day Adventist population.

The interesting thing about the general trend that vegetarians aren't quite as mentally healthy as omnivores (in observational studies) is that vegetarians tend to do better in other measures of health. They are better educated, as a population they are generally younger, less likely to smoke or drink, more likely to exercise, and they tend to care about ethics and the quality of their food. However, vegetarians are also more likely to be female (which is more likely to be associated with anxiety, depression, and eating disorders by a long shot).

So this new study has some things to recommend it. For one thing, the mental health diagnoses were determined not by answers to typical questionnaires, but by a full clinical interview using psychologists or physicians, lasting an average of 65 minutes each. (Pretty impressive, considering there were over 4,000 participants in the population-based study). In addition, the researchers matched omnivores to vegetarians based on age, education, sex, and whether they were urban or rural and crunched those numbers as well, so we got a good sample that took out some of the major confounders that dogged the previous studies. Finally, this cohort was a purposeful random sampling of the German adult population (excluding people over 65, however), rather than the Seventh Day Adventists or adolescents and college students sampled in previous studies.

And when the researchers went down the line of depressive disorders, anxiety disorders, somatoform disorders (things like body dysmorphic disorder, health anxiety and hypochondriasis), and eating disorders, the mostly vegetarian were more likely to be afflicted, and the strict vegetarian even more likely.** The full blown eating disorder diagnoses were rare enough, however, that the researchers didn't compute the odds ratios, as they felt the dataset was not robust enough to be fair. Compared to the general population, the vegetarians were more likely to have mental disorders, and compared to the sex and education and population and age matched controls, the risk of mental disorders in vegetarians really shot up, with odds ratios hovering around 2 fold increased risk, some as high as 3 fold.

When the data was taken apart from another direction, it was found that participants in the study with depressive, anxiety, somatoform, and anxiety disorders consumed less meat than people without a mental disorder. The amount of vegetables, fruits, fish, and fast food did not have a consistent pattern separating those with and without mental disorders (except fish consumption was linked with reduced anxiety. Hmmm). In fact, unlike the 2010 Australian study, those with mental disorders in this German population were less likely to consume fast food than the mentally healthy population.

Temporally, the adoption of a vegetarian diet, on average, tended to follow the mental health diagnosis, suggesting that the vegetarian diet was not in fact causal. I know originally the abstract of the article said the opposite, but if you read the full text, you find that the abstract was misrepresentative. A retrospective study isn't the most robust way to determine this issue, but I would tend to believe this timing to be true, particularly for anxiety disorders, which often begin before the age of 10. The main exception to the temporal findings in this study were the eating disorders, which tended to start right around the same time as adoption of a vegetarian diet. As I've reported before, several of my eating disordered patients have told me they adopted vegetarianism so they would have an excuse to restrict food and not have to eat in public.

So what is going on? In Germany, are the neurotic perfectionists who are more likely to be choosey about food (and thus select vegetarianism and eschew fast food) also more vulnerable to depression and anxiety? Sure, could be. Or maybe those with mental troubles try to avoid what is thought to be bad food (meat and fast food). It is also possible that the nutrient deficiencies common in vegetarian diets (the most robustly studied being long chain omega 3 fatty acids and B12, though I think zinc and creatine and even too low a cholesterol could also be issues) could accelerate or worsen pre-existing mental conditions.

A large study comparing choosey, neurotic, perfectionistic omnivores (ahem) with strict vegetarians would be interesting, I think.

*these cannibals preferentially ate fisherman, who would be chock ful of long chain omega3 fatty acids!!

There are actually very few cultures and religions that are vegetarian, and other than certain Hindu groups all of them are fairly modern, see also the work of Weston Price. There are no traditional cultures that are vegan. Some small groups approach that, such as some Buddhist monks, but even then, they generally eat fish, and it is rarely a lifelong practice. Where there are traditional vegetarian groups they have very specific and complex dietary rules, and incorporate either fish, insects, or dairy, and generally have complex medical traditions using many herbs to combat inflammation. I say this as someone who was a vegetarian for 30 years, and raised three vegetarian children. I suffered from mental health issues, which were completely resolved by first an incredibly complex regimen of supplements, and finally by eating meat. All three of my children have horrible tooth enamel, are of much shorter stature than either my husband or myself, and have other health problems. (So far two have decided to remain vegetarian, and I have respected that choice, though I now encourage them to take a range of supplements. One has started to eat meat and has recovered from several of his lifelong health issues.) I respect totally anyone who can maintain good health as a vegetarian, but I would encourage you to keep an open mind to the reality that other people have suffered horribly from their choice to follow a vegetarian diet.

There are actually very few cultures and religions that are vegetarian, and other than certain Hindu groups all of them are fairly modern, see also the work of Weston Price. There are no traditional cultures that are vegan. Some small groups approach that, such as some Buddhist monks, but even then, they generally eat fish, and it is rarely a lifelong practice. Where there are traditional vegetarian groups they have very specific and complex dietary rules, and incorporate either fish, insects, or dairy, and generally have complex medical traditions using many herbs to combat inflammation. I say this as someone who was a vegetarian for 30 years, and raised three vegetarian children. I suffered from mental health issues, which were completely resolved by first an incredibly complex regimen of supplements, and finally by eating meat. All three of my children have horrible tooth enamel, are of much shorter stature than either my husband or myself, and have other health problems. (So far two have decided to remain vegetarian, and I have respected that choice, though I now encourage them to take a range of supplements. One has started to eat meat and has recovered from several of his lifelong health issues.) I respect totally anyone who can maintain good health as a vegetarian, but I would encourage you to keep an open mind to the reality that other people have suffered horribly from their choice to follow a vegetarian diet.

I belong to one of these cultures and religions that are generations of vegetarians. I agree with few of your points. Also, it depends on if you are a 1st generation vegetarian or it's a generational diet.

I'm having a hard time with this article because from how I'm reading it, it says that vegetarian diet has a causation relationship to mental health whereas there are other variables that play a role in a person's mental state not just diet (be it vegetarian or non vegetarians).

In my opinion this article is poorly written. I don't know how much research writing experience this authors has.

Wow, you didn't read the article very closely. Only at the very end did she even speculate (and was quite clear that it was speculation and not currently supported by the data) that the vegetarian diet could have a causal role in the worsening of already- present mental health disorders. Maybe you need to re- read the article?

Most of the time when i get into this kind of discussion on why people are vego's - most of my friends etc eat vego way because of animal cruelty.

they actually totally get the healthy nod towards meat eaters, but *choose* to not eat meat for the cruelty, mega farmed aspect insert another cruel term in here aspect.

for a paleoesque diet to "win" here - we will need to make grassfed, sustainably farmed meat more available to the greater population.

lucky for me i live in australia - where i can get access to this quite easily. however i feel sorry for my american couterparts where the quality of food is basically pretty bad and to obtain grassfed meat can be expensive.

Clinical studies have found that casein, a protein in all dairy products, blocks the absorption of antioxidants and renders them useless to our body. Get healthier by going vegan! nutritionfacts.org/video/nutrient-blocking-effects-of-dairy/

I mean, I can remember in high school when this one kid in my class ended up getting really sick. He ended up being ill for quite a long time, and with being a vegetarian, he was missing some of the nutrients that could have helped him recover quicker. On the other hand though, a diet which many think is really healthy could actually be not that good for you. For instance, the paleo diet has become pretty popular nowadays, but did you know that many health and nutrition experts disagree over how healthy it really is? If you haven't read anything about this debate yet, you should check out this article at: http://www.availclinical.com/news/paleo-diet-really-healthy-or-really-crazy/

You can't expect someone to switch over from a lifetime of eating something easily can you? That defies any professional medical point of view. Adapting to a vegan/egetarian diet will take time and could initially be hard on the body. Some however will say this is not true and immediately felt better (like me. Some, of course, who may have a longer and more intense genetic history of eating animal obviously wont.

Vegetarianism/Veganism changes the way you think. This is true. However, who says we absolutely need b12/omega 3's? Bollocks. Made up by the people who need to think animal is the only way to live. Regardless I am a health person and I do supplement with these things, from plant sources. I mean hell you can get them from plant sources anyway you know (blue green algae, spirulina, flax seed, borage oil.) If they are so necassary. Not as a supplement which the author neglected to site, I see.

Yes, we vegan/egetarians think different. Yes, I believe this is a more spiritual mind. We're less attuned to common bol shit and more in tune with a higher point of view. Yes, something more spiritual/divine you might call it. THAT is how we think.